SKU: 39366981107

Holley Sniper EFI XFLow 4BBL Self Tuning System - Black Ceramic (HO550-541)

Sale price$1750.95 Regular price$1945.50
Save 10%

Pay in installments of $486.38 with ShopPay, AfterPay and Klarna

Shipping Estimate
USA
  • USA
  • CAN

Ships within 48 hours · Estimated delivery Aug 2 - Aug 7

Promo Codes Available:

For Your Every Summer RSVP, with Code: SUMMER15

Description

Holley Sniper EFI XFLow 4BBL Self Tuning System - Black Ceramic (HO550-541)HO550 541 HOLLEY SNIPER EFI BLACK 800HP 900 cfm 4 Injector Throttle Body, 800 HP N A Part Number: HO550 541 Introducing Sniper EFI XFlow! Are you building a naturally aspirated engine up to 800 Horsepower? Looking to convert your blow through carbureted turbo engine to EFI? Look no further! The Sniper EFI XFlow from Holley features 4, 120LB HR Fuel Injectors and flows 900CFM allowing it safely supporting up to 800 HP on Naturally Aspirated engines.

HO550-541 - HOLLEY SNIPER EFI BLACK 800HP

900 cfm 4 Injector Throttle Body, 800 HP N/A

Part Number: HO550-541

Introducing Sniper EFI XFlow! Are you building a naturally aspirated engine up to 800 Horsepower? Looking to convert your blow through carbureted turbo engine to EFI? Look no further! The Sniper EFI XFlow from Holley features 4, 120LB/HR Fuel Injectors and flows 900CFM allowing it safely supporting up to 800 HP on Naturally Aspirated engines. The XFlow comes with an internal 2.5bar MAP sensor that will safely work on boosted applications up to 21.5 psi. For applications making more than 21.5 psi, and has three additional 0-5v Sensor Inputs which can be used for an external MAP Sensor, or Dome Pressure for boost control, as well as oil pressure and fuel pressure. An External Fuel Pressure regulator is required; we recommend part number 12-848 for N/A applications.
Features:
Supports up to 800HP N/A with 4 120 Lb/Hr Injectors
Flows 900CFM, making it perfect for high rpm N/A engine combinations
Compatibl e with Draw through or Blow through forced induction applications
2.5Bar MAP Sensor
Integrated ignition timing control
Built in Single stage progressive nitrous control
User friendly Boost Control with handheld adjustability
Programm able Target Air Fuel Ratios per Boost level
Advanced boost control available via free Sniper EFI tuning software, including Boost vs RPM and Boost vs Time.
Three Programmable 0-5V Sensor Inputs for Oil/Fuel/Dome or Nitrous Pressure Sensors
Six Programmable Ground Outputs
One +5v Reference Output - +5V Power Supply for 0-5v Sensors
One Sensor Ground - Ground supply for 0-5v Sensors
Dual Pattern bolt on carburetor replacement, designed to fit 4150 Flange & Spread Bore manifolds - (Spread Bore Sealing Plate Part #9006 is recommended)
Throttle body mounted ECU - no extra boxes to mount
Only 4 Wiring Connections Required! (Battery +, Battery - , Switched Ignition & RPM)
Requires an external fuel pressure regulator: P/N 12-848 up to 800 HP
High Resolution Full Color Touchscreen for Initial Setup, Tuning, and Gauge Displays
Simple Calibration Wizard (Answer a few questions about your engine and it creates the base map, then starts tuning on its own!) - NO laptop required!
Self-tuning ECU means you don't have to be a computer/tuning wiz to have EFI!
The included Genuine Bosch LSU 4.9 Wideband Oxygen Sensor provides realtime Fuel Map Learn!
OEM Style TPS/IAC and Fuel Pressure regulator, for years of dependable service.
Included 2.5" clamp-on oxygen sensor kit ensures a leak free oxygen sensor installation, with Stainless Steel T-Bolt clamps and a Stainless Steel (Weldable) oxygen sensor flange

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 39366981107

Discover Niche Categories That Outsell

Top-Converting Item to Boost Your Average Order

4.2 ★★★★★
Based on 13 reviews
Sort
Highest Rating
Newest First
Oldest First
Product Reviews
K
Verified Purchase
Kristen Acosta
San Leandro, US
★★★★★ 5
Previous
Are go to jellies
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 12, 2023
L
Verified Purchase
Los Angeles Mama
San Leandro, US
★★★★★ 4
Love the style- sizing is a bit tricky online
Mini Melissa shoes always deliver on cuteness (and comfort). That said, each pair seems to be slightly different in terms of sizing! We ordered a size 2 and found that it was a little bigger than a recent size 2 we'd ordered. Still worth it, just a heads up that this might be a better purchase in person when you can try on!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 27, 2020
J
Verified Purchase
Julia Vazquez
Pawtucket, US
★★★★★ 5
Durable
Size: 7 Toddler, Color: Black, Size: 7 Toddler, Color: Black
Love melissa shoes so cute great material
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on November 23, 2025
L
Verified Purchase
Lauren Harvey
Charlottesville, US
★★★★★ 5
Adorable!
Size: 7 Toddler, Color: Black
These little shoes are absolutely adorable! I got my 2 year old daughter the black sparkly ones. I originally ordered a size 6, but had to return & swap for a size 7. Not sure if this shoe runs a little small or if my daughter’s foot is just a little big. They are a soft rubber & they smell amazing (I know that sounds weird but when you receive them you will see what I’m talking about lol). They seem like very good quality & like they will last awhile, especially on a 2 year old who is hard on shoes!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 20, 2024
N
Verified Purchase
Normabee
Louisville, US
★★★★★ 5
They are comfortable daughters
Size: 12 Little Kid, Color: Pearly White/Black
Soft and comfortable for my 6 year old. She loves to wear them with dresses.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 31, 2026

recommand products